A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 12.04 ESM

Summary:

Several security issues were fixed in the Linux kernel.

Software Description:- linux: Linux kernel

Details:

Jann Horn discovered that microprocessors utilizing speculative executionand branch prediction may allow unauthorized memory reads via sidechannelattacks. This flaw is known as Spectre. A local attacker could use this toexpose sensitive information, including kernel memory.

Update instructions:

The problem can be corrected by updating your system to the followingpackage versions:

Please note that fully mitigating CVE-2017-5715 (Spectre Variant 2)requires corresponding processor microcode/firmware updates or,in virtual environments, hypervisor updates. On i386 and amd64architectures, the IBRS and IBPB features are required to enable thekernel mitigations. Ubuntu is working with Intel and AMD to providefuture microcode updates that implement IBRS and IBPB as they are madeavailable. Ubuntu users with a processor from a different vendor shouldcontact the vendor to identify necessary firmware updates. Ubuntuwill provide corresponding QEMU updates in the future for users ofself-hosted virtual environments in coordination with upstream QEMU.Ubuntu users in cloud environments should contact the cloud providerto confirm that the hypervisor has been updated to expose the newCPU features to virtual machines.

After a standard system update you need to reboot your computer toapply the necessary changes.